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Speakers design communication for their audience, providing more information in both speech and gesture when their listener is naïve to the topic. We test whether the hippocampal declarative memory system contributes to multimodal audience design. The hippocampus, while traditionally linked to episodic and relational memory, has also been linked to the ability to imagine the mental states of others and use language flexibly. We examined the speech and gesture use of four patients with hippocampal amnesia when describing how to complete everyday tasks (e.g., how to tie a shoe) to an imagined child listener and an adult listener. Although patients with amnesia did not increase their total number of words and instructional steps for the child listener, they did produce representational gestures at significantly higher rates for the imagined child compared to the adult listener. They also gestured at similar frequencies to neurotypical peers, suggesting that hand gesture can be a meaningful communicative resource, even in the case of severe declarative memory impairment. We discuss the contributions of multiple memory systems to multimodal audience design and the potential of gesture to act as a window into the social cognitive processes of individuals with neurologic disorders. [ABSTRACT FROM AUTHOR]

As an intermediate state between normal aging and dementia, mild cognitive impairment (MCI), especially amnestic MCI (aMCI), is a key stage in the prevention and intervention of Alzheimer's disease (AD). Whether dancing could increase the hippocampal volume of seniors with aMCI remains debatable. The aim of this study was to investigate the influence of aerobic dance on hippocampal volume and cognition after 3 months of aerobic dance in older adults with aMCI. In this randomized controlled trial, 68 elderly people with aMCI were randomized to either the aerobic dance group or the control group using a 1:1 allocation ratio. Ultimately, 62 of 68 participants completed this study, and the MRI data of 54 participants were included. A specially designed aerobic dance routine was performed by the dance group three times per week for 3 months, and all participants received monthly healthcare education after inclusion. MRI with a 3.0T MRI scanner and cognitive assessments were performed before and after intervention. High-resolution three-dimensional (3D) T1-weighted anatomical images were acquired for the analysis of hippocampal volume. A total of 35 participants (mean age: 71.51 ± 6.62 years) were randomized into the aerobic dance group and 33 participants (mean age: 69.82 ± 7.74 years) into the control group. A multiple linear regression model was used to detect the association between intervention and the difference of hippocampal volumes as well as the change of cognitive scores at baseline and after 3 months. The intervention group showed greater right hippocampal volume (β [95% CI]: 0.379 [0.117, 0.488], p = 0.002) and total hippocampal volume (β [95% CI]: 0.344 [0.082, 0.446], p = 0.005) compared to the control group. No significant association of age or gender was found with unilateral or global hippocampal volume. There was a correlation between episodic memory and intervention, as the intervention group showed a higher Wechsler Memory Scale-Revised Logical Memory (WMS-RLM) score (β [95% CI]: 0.326 [1.005, 6.773], p = 0.009). Furthermore, an increase in age may cause a decrease in the Mini-Mental State Examination (MMSE) score (β [95% CI]: −0.366 [−0.151, −0.034], p = 0.002). In conclusion, 3 months of aerobic dance could increase the right and total hippocampal volumes and improve episodic memory in elderly persons with aMCI. Clinical Trial Registration: This study was registered on the Chinese Clinical Trial Registry [www.chictr.org.cn], identifier [ChiCTR-INR-15007420]. [ABSTRACT FROM AUTHOR]

• Meal-related memory inhibits eating in humans. • Amnesia is associated with overeating and impaired interoception in humans. • Research in rodents and humans implicates the hippocampus in these effects. • Obesity disrupts memory and hippocampal functioning in rodents and humans. • These effects of obesity may create a vicious cycle that perpetuates obesity. This paper reviews evidence demonstrating a bidirectional relationship between memory and eating in humans and rodents. In humans, amnesia is associated with impaired processing of hunger and satiety cues, disrupted memory of recent meals, and overconsumption. In healthy participants, meal-related memory limits subsequent ingestive behavior and obesity is associated with impaired memory and disturbances in the hippocampus. Evidence from rodents suggests that dorsal hippocampal neural activity contributes to the ability of meal-related memory to control future intake, that endocrine and neuropeptide systems act in the ventral hippocampus to provide cues regarding energy status and regulate learned aspects of eating, and that consumption of hypercaloric diets and obesity disrupt these processes. Collectively, this evidence indicates that diet-induced obesity may be caused and/or maintained, at least in part, by a vicious cycle wherein excess intake disrupts hippocampal functioning, which further increases intake. This perspective may advance our understanding of how the brain controls eating, the neural mechanisms that contribute to eating-related disorders, and identify how to treat diet-induced obesity. [ABSTRACT FROM AUTHOR]

Patients with Alzheimer's disease (AD) suffer from various types of memory distortions. We showed that confabulations are plausible memories, mainly reflecting the recall of repeated personal events mistakenly considered by confabulating patients as specific and unique events. The aim of this study is to see whether the notion that over-learned information interferes in episodic memory recall, as it does in confabulation, can be extended to another type of memory distortion, namely false recognition (i.e., a claim to recognize something that was not encountered previously). If this is the case, it should be expected that in an episodic recognition memory task AD patients produce more false recognition for well known non-studied, non to-be-remembered material than for unknown non-studied, non to-be-remembered material. In order to verify this prediction, AD patients and normal controls (NC) were administered two experiments. In Experiment 1, we presented pictures, of which half were supposed to be well known and the other half unknown monuments. For each picture, participants were asked to say whether or not the monument was known or not to them. Immediately following this semantic encoding task, participants were administered an episodic recognition memory task in which, in the same way as in the previous phase, among the non-studied items, half were supposed to be well known and the other half unknown. In Experiment 2 the same procedure was used employing well known and unknown symbols. It was predicted that AD patients make more false recognitions for non-studied well-known items than for non-studied unknown items. The results show that this is actually the case, suggesting that confusion between "uniqueness," i.e., specific unique events, and "multiplicity," i.e., repeated events, is also involved in false recognition. [ABSTRACT FROM AUTHOR]

Numerous evidences suggest the existence of relationships between the impairment of episodic memory, acute stress exposure and variations in self-awareness (SA). Here, we examined 27 patients presenting transient global amnesia (TGA), a clinical condition which combines episodic amnesia and high anxiety, thanks to state and trait questionnaires of SA. We observed variation of SA depending on the stage of TGA (acute, recovery and follow-up). We also found preexisting differences in patient's awareness of their own image when the precipitating event was physical, encouraging us to give more consideration to the social determinants of stress in physiological cascade of TGA. [ABSTRACT FROM AUTHOR]

Deep inside the temporal lobe of the brain, the hippocampus has a central role in our ability to remember, imagine and dream.

The hippocampus is linked with both sleep and memory, but there is debate about whether a salient aspect of sleep – dreaming – requires its input. To address this question, we investigated if human patients with focal bilateral hippocampal damage and amnesia engaged in dreaming. We employed a provoked awakening protocol where participants were woken up at various points throughout the night, including during non-rapid eye movement and rapid eye movement sleep, to report their thoughts in that moment. Despite being roused a similar number of times, dream frequency was reduced in the patients compared to control participants, and the few dreams they reported were less episodic-like in nature and lacked content. These results suggest that hippocampal integrity may be necessary for typical dreaming to occur, and aligns dreaming with other hippocampal-dependent processes such as episodic memory that are central to supporting our mental life.

Many decisions require flexible reasoning that depends on inference, generalization, and deliberation. Here, we review emerging findings indicating that the hippocampus, known for its role in long-term memory, contributes to these flexible aspects of value-based decision-making. This work offers new insights into the role of memory in decision-making and suggests that memory may shape decisions even in situations that do not appear, at first glance, to depend on memory at all. Uncovering the pervasive role of memory in decision-making challenges the way we define what memory is and what it does, suggesting that memory's primary purpose may be to guide future behavior and that storing a record of the past is just one way to do so. Memory plays a pervasive role in flexible decision-making that depends on inference, generalization, and deliberation. This function of memory in decision-making is supported by the hippocampus, suggesting that the role of the hippocampus may be to create a record of the past in the service of future behavior. This view reconciles findings from the fields of memory and decision-making. It offers new insight into why some memories are prioritized over others, why memory loss sometimes leads to impaired decision-making, and why decisions are shaped by regret and counterfactual thinking. [ABSTRACT FROM AUTHOR]

Memories for events that happen early in life are fragile—they are forgotten more quickly than expected based on typical adult rates of forgetting. Although numerous factors contribute to this phenomenon, data show that one major source of change is the protracted development of neural structures related to memory. Recent empirical studies in early childhood reveal that the development of specific subdivisions of the hippocampus (i.e., the dentate gyrus) is related directly to variations in memory. Yet, the hippocampus is only one region within a larger network supporting memory. Data from young children have also shown that activation of cortical regions during memory tasks and the functional connectivity between the hippocampus and cortex relate to memory during this period. Taken together, these results suggest that protracted neural development of the hippocampus, cortex, and connections between these regions contribute to the fragility of memories early in life and may ultimately contribute to childhood amnesia. [ABSTRACT FROM AUTHOR]

To understand the neural basis of episodic memory it is necessary to appreciate the significance of the fornix. This pathway creates a direct link between those temporal lobe and medial diencephalic sites responsible for anterograde amnesia. A collaboration with Andrew Mayes made it possible to recruit and scan 38 patients with colloid cysts in the third ventricle, a condition associated with variable fornix damage. Complete fornix loss was seen in three patients, who suffered chronic long-term memory problems. Volumetric analyses involving all 38 patients then revealed a highly consistent relationship between mammillary body volume and the recall of episodic memory. That relationship was not seen for working memory or tests of recognition memory. Three different methods all supported a dissociation between recollective-based recognition (impaired) and familiarity-based recognition (spared). This dissociation helped to show how the mammillary body-anterior thalamic nuclei axis, as well as the hippocampus, is vital for episodic memory yet is not required for familiarity-based recognition. These findings set the scene for a reformulation of temporal lobe and diencephalic amnesia. In this revised model, these two regions converge on overlapping cortical areas, including retrosplenial cortex. The united actions of the hippocampal formation and the anterior thalamic nuclei on these cortical areas enable episodic memory encoding and consolidation, impacting on subsequent recall. [Display omitted] • Dissociation of recall from recognition in closely matched patient groups. • Mammillary body atrophy predicts levels of episodic memory recall. • Deconstruction of Papez circuit. • Diencephalic and temporal lobe sites create vital supports in unified memory system. • Spotlight on convergent inputs to medial cortical areas for consolidation. [ABSTRACT FROM AUTHOR]

Recent evidence suggests that the human hippocampus—known primarily for its involvement in episodic memory—plays a role in a host of motivationally relevant behaviors, including some forms of value-based decision-making. However, less is known about the role of the hippocampus in value-based learning. Such learning is typically associated with a striatal system, yet a small number of studies, both in human and nonhuman species, suggest hippocampal engagement. It is not clear, however, whether this engagement is necessary for such learning. In the present study, we used both functional MRI (fMRI) and lesion-based neuropsychological methods to clarify hippocampal contributions to value-based learning. In Experiment 1, healthy participants were scanned while learning value-based contingencies (whether players in a "game" win money) in the context of a probabilistic learning task. Here, we observed recruitment of the hippocampus, in addition to the expected ventral striatal (nucleus accumbens) activation that typically accompanies such learning. In Experiment 2, we administered this task to amnesic patients with medial temporal lobe damage and to healthy controls. Amnesic patients, including those with damage circumscribed to the hippocampus, failed to acquire value-based contingencies, thus confirming that hippocampal engagement is necessary for task performance. Control experiments established that this impairment was not due to perceptual demands or memory load. Future research is needed to clarify the mechanisms by which the hippocampus contributes to value-based learning, but these findings point to a broader role for the hippocampus in goal-directed behaviors than previously appreciated. [ABSTRACT FROM AUTHOR]

The hippocampus plays a critical role in episodic memory and imagination. One theoretical model posits that the hippocampus is important for scene construction, namely, the ability to conjure and maintain a scene-based representation in one's mind. To test one idea put forth by this view, we examined whether amnesia is associated with more severe impairment in memory when the to-be-remembered content places high demands on scene construction. To do so, we examined free recall performance for abstract (i.e., low scene imagery) and concrete, high scene-imagery single words in seven amnesic patients with hippocampal lesions and concomitant scene-construction deficits, and compared their performance to demographically matched healthy controls. As expected, amnesic patients were severely impaired in their free recall performance; however, their impairment did not differ as a function of word type. That is, their impairment was equally severe for words that evoke high versus low scene imagery. These findings suggest that the role of the hippocampus in verbal memory extends to content that does not place high demands on scene construction. Theoretical implications of these findings are discussed. • Amnesic patients with hippocampal damage were tested on a free recall task. • Words were either low or high in scene imagery. • Patients showed equivalent free recall impairment for both word types. • These findings show that amnesia does not always confer greater impairment for scene-based content. [ABSTRACT FROM AUTHOR]

An important theory holds that semantic knowledge can develop independently of episodic memory. One strong source of evidence supporting this independence comes from the observation that individuals with early hippocampal damage leading to developmental amnesia generally perform normally on standard tests of semantic memory, despite their profound impairment in episodic memory. However, one aspect of semantic memory that has not been explored is conceptual structure. We built on the theoretically important distinction between intrinsic features of object concepts (e.g., shape, colour, parts) and extrinsic features (e.g., how something is used, where it is typically located). The accrual of extrinsic feature knowledge that is important for concepts such as chair or spoon may depend on binding mechanisms in the hippocampus. We tested HC, an individual with developmental amnesia due to a well-characterized lesion of the hippocampus, on her ability to generate semantic features for object concepts. HC generated fewer extrinsic features than controls, but a similar number of intrinsic features than controls. We also tested her on typicality ratings. Her typicality ratings were abnormal for nonliving things (which more strongly depend on extrinsic features), but normal for living things (which more strongly depend on intrinsic features). In contrast, NB, who has MTL but not hippocampal damage due to surgery, showed no impairments in either task. These results suggest that episodic and semantic memory are not entirely independent, and that the hippocampus is important for learning some aspects of conceptual knowledge. [ABSTRACT FROM AUTHOR]

In two experiments, patients with damage to the medial temporal lobe (MTL) and healthy controls produced detailed autobiographical narratives as they remembered past events (recent and remote) and imagined future events (near and distant). All recent events occurred after the onset of memory impairment. The first experiment aimed to replicate the methods of Race et al. [Race E, KeaneMM, Verfaellie M (2011) J Neurosci 31(28):10262-10269]. Transcripts from that study were kindly made available for independent analysis, which largely reproduced the findings from that study. Our patients produced marginally fewer episodic details than controls. Patients from the earlier study were more impaired than our patients. Patients in both groups had difficulty in returning to their narratives after going on tangents, suggesting that anterograde memory impairment may have interfered with narrative construction. In experiment 2, the experimenter used supportive questioning to help keep participants on task and reduce the burden on anterograde memory. This procedure increased the number of details produced by all participants and rescued the performance of our patients for the distant past. Neither of the two patient groups had any special difficulty in producing spatial details. The findings suggest that constructing narratives about the remote past and the future does not depend on MTL structures, except to the extent that anterograde amnesia affects performance. The results further suggest that different findings about the status of autobiographical memory likely depend on differences in the location and extent of brain damage in different patient groups. [ABSTRACT FROM AUTHOR]

Summary Our day-to-day experiences are often similar to one another, occurring in the same place at the same time of day, with common people and objects, and with a shared purpose. Humans have an episodic memory to represent unique, personal events that are rich in detail [ 1 ]. For this to occur, at least two basic neural mechanisms are required: one to orthogonalize or “separate” overlapping input patterns at encoding and another to reinstate or “complete” memories from partial cues at retrieval [ 2–6 ]. To what extent do these purported “pattern separation” and “pattern completion” mechanisms rely on distinct subfields of the hippocampus [ 6 ]? Computational models [ 4–6 ] and lesion and genetic studies in rodents [ 7–12 ] largely point to the dentate gyrus as responsible for pattern separation and the CA3 and CA1 subfields for pattern completion (but see [ 13–16 ]). In high-resolution fMRI studies of humans, behavioral discrimination and completion tasks designed to approximate pattern separation and pattern completion, respectively, elicit the predicted pattern of activity in the dentate gyrus and CA3/CA1 [ 17–21 ]. Likewise, impaired behavioral discrimination has been demonstrated in individuals with hippocampal lesions [ 22, 23 ], but the lesions most likely encompass other subfields. Examination of these processes in individuals with selective lesions to hippocampal subfields is needed to infer causation [ 19 ]. Here, we report the rare case of BL, a 54-year-old man with bilateral ischemic lesions to the hippocampus [ 24 ] primarily affecting the dentate gyrus. Studying BL provides the unique opportunity to directly evaluate theories of hippocampal function that assign the dentate gyrus a specific role in discriminating old from new memories. [ABSTRACT FROM AUTHOR]

After more than 80 years, Papez serial circuit remains a hugely influential concept, initially for emotion, but in more recent decades, for memory. Here, we show how this circuit is anatomically and mechanistically naïve as well as outdated. We argue that a new conceptualisation is necessitated by recent anatomical and functional findings that emphasize the more equal, working partnerships between the anterior thalamic nuclei and the hippocampal formation, along with their neocortical interactions in supporting, episodic memory. Furthermore, despite the importance of the anterior thalamic for mnemonic processing, there is growing evidence that these nuclei support multiple aspects of cognition, only some of which are directly associated with hippocampal function. By viewing the anterior thalamic nuclei as a multifunctional hub, a clearer picture emerges of extra-hippocampal regions supporting memory. The reformulation presented here underlines the need to retire Papez serially processing circuit. • Why it is time for the concept of Papez circuit to be retired. • The anterior thalamic nuclei and hippocampus conjointly support episodic memory. • Focus should now shift to how these two structures jointly interact with neocortex. • Some anterior thalamic functions are independent of the hippocampus. • The anterior thalamic nuclei provide a multifunctional hub. [ABSTRACT FROM AUTHOR]

Patients with developmental amnesia usually suffer from both episodic and spatial memory deficits. DM, a developmental amnesic, was impaired in her ability to process self-motion (i.e., idiothetic) information while her ability to process external stable landmarks (i.e., allothetic) was preserved when no self-motion processing was required. On a naturalistic and incidental episodic task, DM was severely and predictably impaired on both free and cued recall tasks. Interestingly, when cued, she was more impaired at recalling spatial context than factual or temporal information. Theoretical implications of that co-occurrence of deficits and those dissociations are discussed and testable cerebral hypothesis are proposed. [ABSTRACT FROM AUTHOR]

ABSTRACT We often engage in counterfactual (CF) thinking, which involves reflecting on 'what might have been.' Creating alternative versions of reality seems to have parallels with recollecting the past and imagining the future in requiring the simulation of internally generated models of complex events. Given that episodic memory and imagining the future are impaired in patients with hippocampal damage and amnesia, we wondered whether successful CF thinking also depends upon the integrity of the hippocampus. Here using two nonepisodic CF thinking tasks, we found that patients with bilateral hippocampal damage and amnesia performed comparably with matched controls. They could deconstruct reality, add in and recombine elements, change relations between temporal sequences of events, enabling them to determine plausible alternatives of complex episodes. A difference between the patients and control participants was evident, however, in the patients' subtle avoidance of CF simulations that required the construction of an internal spatial representation. Overall, our findings suggest that mental simulation in the form of nonepisodic CF thinking does not seem to depend upon the hippocampus unless there is the added requirement for construction of a coherent spatial scene within which to play out scenarios. © 2014 The Authors. Hippocampus Published by Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Spatial navigation and event memory (termed episodic memory) are thought to be heavily intertwined, both in terms of their cognitive processes and underlying neural systems. Some theoretical models posit that both memory for places during navigation and episodic memory depend on highly overlapping brain systems. Here, we assessed this relationship by testing navigation in an individual with severe retrograde and anterograde amnesia; the amnesia stemmed from bilateral lesions in the medial temporal lobes from two separate strokes. The individual with amnesia and age-matched controls were tested on their memories for the locations of previously seen objects relative to distal mountain cues in an immersive virtual environment involving free ambulation. All participants were tested from both repeated and novel start locations and when a single distal mountain cue was unknowingly moved to determine if they relied on a single (beacon) cue to a greater extent than the collection of all distal cues. Compared to age-matched controls, the individual with amnesia showed no significant deficits in navigation from either the repeated or novel start points, although both the individual with amnesia and controls performed well above chance at placing objects near their correct locations. The individual with amnesia also relied on a combination of distal cues in a manner comparable to age-matched controls. Despite largely intact memory for locations using distal cues, the individual with amnesia walked longer paths, rotated more, and took longer to complete trials. Our findings suggest that memory for places during navigation and episodic memory may involve partially dissociable brain circuits and that other brain regions outside of the medial temporal lobe partially support some aspects of navigation. At the same time, the fact that the individual with amnesia walked more circuitous paths and had dense amnesia for autobiographic events supports the idea that the hippocampus may be important for binding information as part of a larger role in memory. • We tested a person with severely impaired episodic memory on a spatial task with free ambulation and hidden target objects. • This individual had a bilateral lesion to the medial temporal lobes due to two separate strokes. • The individual performed comparably to controls and above chance at finding the hidden targets using distal cues. • Our findings support episodic and place memory involving partially dissociable brain circuits during navigation. [ABSTRACT FROM AUTHOR]

Difficulties remembering one’s own experiences via episodic memory may affect the ability to imagine other people’s experiences during theory of mind (ToM). Previous work shows that the same set of brain regions recruited during tests of episodic memory and future imagining are also engaged during standard laboratory tests of ToM. However, hippocampal amnesic patients who show deficits in past and future thinking, show intact performance on ToM tests, which involve unknown people or fictional characters. Here we present data from a developmental amnesic person (H.C.) and a group of demographically matched controls, who were tested on a naturalistic test of ToM that involved imagining other people’s experiences in response to photos of personally familiar others (‘pToM’ condition) and unfamiliar others (‘ToM’ condition). We also included a condition that involved recollecting past experiences in response to personal photos (‘EM’ condition). Narratives were scored using an adapted autobiographical interview scoring procedure. Due to the visually rich stimuli, internal details were further classified as either descriptive (i.e., details that describe the visual content depicted in the photo) or elaborative (i.e., details that go beyond what is visually depicted in the photo). Relative to controls, H.C. generated significantly fewer elaborative details in response to the pToM and EM photos and an equivalent number of elaborative details in response to the ToM photos. These data converge with previous neuroimaging results showing that the brain regions underlying pToM and episodic memory overlap to a greater extent than those supporting ToM. Taken together, these results suggest that detailed episodic representations supported by the hippocampus may be pivotal for imagining the experiences of personally familiar, but not unfamiliar, others.

On the face of it, memory, imagination, and prediction seem to be distinct cognitive functions. However, metacognitive, cognitive, neuropsychological, and neuroimaging evidence is emerging that they are not, suggesting intimate links in their underlying processes. Here, we explore these empirical findings and the evolving theoretical frameworks that seek to explain how a common neural system supports our recollection of times past, imagination, and our attempts to predict the future. [ABSTRACT FROM PUBLISHER]

The current ubiquity of functional neuroimaging studies, and the importance they have had in elucidating brain function, obscures the fact that much of what we know about brain-behavior relationships derives largely from the study of single- and multiple-patient cases. A major goal of the present review is to describe how single cases continue to uniquely and critically contribute to cognitive neuroscience theory. With several recent examples from the literature, we demonstrate that single cases can both challenge accepted dogma and generate hypotheses and theories that steer the field in new directions. We discuss recent findings from case studies that specify critical functions of the hippocampus in episodic memory and recollection, and clarify its role in nonmnemonic abilities. Although we focus on the hippocampus, we discuss other regions and the occurrence of new associative learning, as well as the involvement of the ventromedial prefrontal and parietal cortices in memory encoding and retrieval. We also describe ways of dealing with the shortcomings of case studies, and emphasize the partnership of patient and neuroimaging methods in constraining neurocognitive models of memory. [ABSTRACT FROM AUTHOR]

Abstract: Amnesic patients with bilateral hippocampal damage sustained in adulthood are generally unable to construct scenes in their imagination. By contrast, patients with developmental amnesia (DA), where hippocampal damage was acquired early in life, have preserved performance on this task, although the reason for this sparing is unclear. One possibility is that residual function in remnant hippocampal tissue is sufficient to support basic scene construction in DA. Such a situation was found in the one amnesic patient with adult-acquired hippocampal damage (P01) who could also construct scenes. Alternatively, DA patients’ scene construction might not depend on the hippocampus, perhaps being instead reliant on non-hippocampal regions and mediated by semantic knowledge. To adjudicate between these two possibilities, we examined scene construction during functional MRI (fMRI) in Jon, a well-characterised patient with DA who has previously been shown to have preserved scene construction. We found that when Jon constructed scenes he activated many of the regions known to be associated with imagining scenes in control participants including ventromedial prefrontal cortex, posterior cingulate, retrosplenial and posterior parietal cortices. Critically, however, activity was not increased in Jon's remnant hippocampal tissue. Direct comparisons with a group of control participants and patient P01, confirmed that they activated their right hippocampus more than Jon. Our results show that a type of non-hippocampal dependent scene construction is possible and occurs in DA, perhaps mediated by semantic memory, which does not appear to involve the vivid visualisation of imagined scenes. [Copyright &y& Elsevier]

We currently lack a unified and mechanistic account of how the hippocampus supports a range of disparate cognitive functions that includes episodic memory, imagining the future, and spatial navigation. Here, we argue that in order to leverage this long-standing issue, traditional notions regarding the architecture of memory should be eschewed. Instead, we invoke the idea that scenes are central to hippocampal information processing. This view is motivated by mounting evidence that the hippocampus is constantly constructing spatially coherent scenes, automatically anticipating and synthesizing repre-sentations of the world beyond the immediate sensorium. By characterizing the precise relationship between scenes and the hippocampus, we believe a theoretically enriched understanding of its funda-mental role and its breakdown in pathology can emerge. [ABSTRACT FROM AUTHOR]

The role of the medial temporal lobes (MTL) in short-term memory (STM) remains a matter of debate. Whereas imaging studies commonly show hippocampal activation during short-delay memory tasks, evidence from amnesic patients with MTL lesions is mixed. It has been argued that apparent STM impairments in amnesia may reflect long-term memory (LTM) contributions to performance. We challenge this conclusion by demonstrating that MTL amnesic patients show impaired delayed matching-to-sample (DMS) for faces in a task that meets both a traditional delay-based and a recently proposed distractor-based criterion for classification as an STM task. In Experiment 1, we demonstrate that our face DMS task meets the proposed distractor-based criterion for STM classification, in that extensive processing of delay-period distractor stimuli disrupts performance of healthy individuals. In Experiment 2, MTL amnesic patients with lesions extending into anterior subhippocampal cortex, but not patients with lesions limited to the hippocampus, show impaired performance on this task without distraction at delays as short as 8 s, within temporal range of delay-based STM classification, in the context of intact perceptual matching performance. Experiment 3 provides support for the hypothesis that STM for faces relies on configural processing by showing that the extent to which healthy participants' performance is disrupted by interference depends on the configural demands of the distractor task. Together, these findings are consistent with the notion that the amnesic impairment in STM for faces reflects a deficit in configural processing associated with subhippocampal cortices and provide novel evidence that the MTL supports cognition beyond the LTM domain. [ABSTRACT FROM AUTHOR]